Thread: Anyone use an Anderson Weight Distribution Hitch

I tow with a Discovery 4 my van has a 320kg ball weight.

I towed a fair bit so I know how the thing behaves in many conditions.

The OP here I believe may just be over correcting when he feels movement its not first time I have heard of people doing this.

Small movements from the van can feel huge but what you need to is have faith in rig resist the urge to correct (unless you are headed for ditch) you may be very surprised to see your rig correct its self and keep going. Adding more input just simply makes it worse.

If things are going to go bad the trailer stability system will take control I have experienced this 3 times and each time I let the D4 handle it.

^ this guy knows his stuff! Done a lot of miles with his van on the back!

Originally Posted by simmo1

With a caravan when you might have a ball load of say between 250 to 350kg. Application of physics says that this must reduce the axle load to the steer wheels.

Sort of. What it does is increase the load at the rear, which moves the centre of gravity rearwards, putting more load on the rear and less on the front to balance the moment around the CofG, as the front axle is now further away from the CofG and the rear closer.

However this ignores an important point. The springs provide a reaction to the load from the weight of vehicle. With normal springs this reaction is constant giving the the usual sag at the rear and lightening at the front. However air suspension has a variable spring rate so varies its reaction relative to the load applied through the self-levelling process.

So in effect, because there is a greater reaction at the rear to counter the additional weight on the towball, there is no weight transferred from the front.

Now I don't know much about weight distribution hitches and towing caravans (and want to keep it that way) so someone needs to educate me on them. My understanding of how a weight distribution hitch works is that it basically applies a lever to the towball. Doesn't this effectively reduce the ball weight?

Cheers,
Jon

Originally Posted by jon3950

So in effect, because there is a greater reaction at the rear to counter the additional weight on the towball, there is no weight transferred from the front.

I disagree. The rear axle becomes a fulcrum when load is added behind the axle causing weight on the front axle to be reduced, van or no van.

What rear tyre pressure are you using? They need to be harder than needed for simply the extra load in order to stay more rigid when the van moves.

I agree with Mowog - don't get too concerned with keeping the rig absolutely rigid, just keep steering as though nothing is happening and your confidence will improve.

BTW, LR only do not recommend the use of a WDH. If you use one make sure that the rear is not lifted up to normal height by the WDH to give the suspension the task of carrying some of the extra load.

I would look at the van tyres,air pressure is important as suggested.
Make sure they are a decent brand and light truck type.The sidewalls are stronger and will flex less as the caravan wobbles.Truckies and Traffic controlers refer to caravans as wobblies
My boat trailer wobbled behind the D2,partly due to the way the previous owner set the trailer up,mainly due to the oem trailer tyres.I shifted the boat a bit closer to the hich and replaced the tyres with quality Yokahama LT tyres.It still twiched after the boat was moved forward the tyres fixed the problem.It was never goint to throw the D2 off the road,just was a pain to feel it wagging the tail when set off by cross winds or trucks.
Andrew

I tow very heavy trailers and often.

My Touareg is a superior tow vehicle than my D4 with a heavy ball weight....but on the VW I use a WDH.

My wife first commented about the D4 not being as nice to tow than our Touareg....but she hated setting up the Hayman Reece WDH.

On one occasion I towed using the same WDH with the same trailer on my D4 for about a 400km return trip. It was a vastly superior tow than relying on airbags along. None of the rear end bouncing/floating (whatever people want to call it) that the D4 goes through with 345kgs on the ball.

I only did it once as its not recommended, but for that trip it was noticeable a more enjoyable tow and caused no issues with the air suspension.

Brett...

I suspect the reason for the recommendation is because if set too high then the pressure in the rear springs will be inappropriately reduced trying to make the rear lower. There is no simple gauge to indicate to an uninformed user just how much load to transfer to the front, although its easy to judge if the air suspension is disabled before attaching the van and the WDH.

Originally Posted by Graeme

I disagree. The rear axle becomes a fulcrum when load is added behind the axle causing weight on the front axle to be reduced, van or no van.

Because the additional weight is cantilevered behind the rear axle which moves the CofG closer to the rear axle, it appears to do this. However everything actually rotates around the CofG which will always be forward of the rear axle, unless the vehicle is overloaded. The reaction from the rear springs is also behind the CofG and the point is with air suspension this reaction can be increased to counter the additional load.

The problem though is that a towball weight is actually a dynamic load when you are moving, increasing and decreasing as the trailer pitches. This means that the CofG is continually moving, which if great enough will make the vehicle feel unstable.

Cheers,
Jon